On our first cruise, I decided (stupidly) that we really weren't in a hurry to get to the ship. We ate a leisurly lunch at our WDW hotel, finished packing up the car and then drove to the port. We arrived around 2pm. Didn't realize that they would have lunch for us, that the pools would be open, that the ship would be that interesting (and beautiful) and that we could get the children registered for the kids clubs, and that by arriving "so late" that we would be totally stressed for the first 6 or seven hours of the cruise part of our vacation.
We wised up for the second cruise (and found another board-before finding this one)!! We had
DCL transfers from the airport. We arrived at the airport and were on one of the first buses leaving for the port. We arrived between 10:30 and 11am, got checked in, waited in line to board the ship, got on early, had lunch outside at topsiders, made our Palo resie for brunch, signed the in to the kids clubs, decided to try a spa treatment (but were too late for that - but not really a big deal), wandered around the ship getting reaquanted with her (and she is a beauty!). When the time came for the drill, we were ready, then were ready to party on at the sail away party, then a little later was dinner (early seating). What a great day!! And we just barely had left the dock.
Overall the second embarkation process was much more enjoyable, less stressful and set the tone for the next 7 days. Even if you don't need to / want to make any ressies, I would highly recommend arriving early.
Enjoy!